package com.project.projectdemo.conf.filter;

import java.io.IOException;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.Date;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.lang.Nullable;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import com.google.gson.JsonObject;

/**
 * 日志拦截器组件
 * @author liushgc	2020-02-11
 *
 */
public class LoggerInterceptor extends HandlerInterceptorAdapter {
	
	
	/**  
     * 在业务处理器处理请求之前被调用  
     * 如果返回false  
     *     从当前的拦截器往回执行所有拦截器的afterCompletion(),再退出拦截器链 
     * 如果返回true  
     *    执行下一个拦截器,直到所有的拦截器都执行完毕  
     *    再执行被拦截的Controller  
     *    然后进入拦截器链,  
     *    从最后一个拦截器往回执行所有的postHandle()  
     *    接着再从最后一个拦截器往回执行所有的afterCompletion()  
     */ 
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
			throws Exception {
		System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date())+" 入口拦截");
		return true;
	}
	
	/** 
     * 在业务处理器处理请求执行完成后,生成视图之前执行的动作    
     * 可在modelAndView中加入数据，比如当前时间 
     */  
	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
			@Nullable ModelAndView modelAndView) throws Exception {
		System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date())+" 业务结束后拦截");
	}
	
	/**  
     * 在DispatcherServlet完全处理完请求后被调用,可用于清理资源等   
     *   
     * 当有拦截器抛出异常时,会从当前拦截器往回执行所有的拦截器的afterCompletion()  
     */  
	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
			@Nullable Exception ex) throws Exception {
		System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date())+" 出口拦截");
	}
	
	
	
	//返回参数
	private void returnResult(HttpServletResponse response,JsonObject json){
		PrintWriter writer = null;
		response.setCharacterEncoding("UTF-8");
        response.setContentType("text/json; charset=utf-8");
		try {
			writer = response.getWriter();
			writer.print(json);
			writer.flush();
		} catch (IOException e) {
			
		}finally{
			if(writer!=null){
				writer.close();
			}
		}
	}
	
}
